Heating up three cold cases in Norway using investigative genetic genealogy.

With the advent of commercial DNA databases, investigative genetic genealogy (IGG) has emerged as a powerful forensic tool, rivalling the impact of STR analyses, introduced four decades ago. IGG has been frequently applied in the US and tested in other countries, but never in Norway. Here, we apply IGG to three cold criminal cases and successfully identify the donor of the DNA in two of these cases. Our findings suggest that when combined with phenotypic prediction and case information, IGG holds substantial potential for resolving both active and cold cases in Norway. This potential is amplified by the digitalization of archives and the transparent and structured nature of society in Norway. Additionally, the databases exhibit sufficient representation to yield matches with distant relatives. Moreover, this work has uncovered a series of lingering research questions spanning the entire workflow from DNA extraction to genealogy research. Finally, we highlight the possibility that more insights can be gleaned from genetic profiles, for instance using an accurate age prediction method. The results show that IGG can be successfully applied in Norway, having reached a level of maturity that enables identification of unknown individuals in cases where DNA is accessible.